This invention relates to a process for preparing 2-benzimidazole carbamate compounds. More particularly, this application describes a method for preparing alkyl 5alkylthio-2-benzimidazole carbamate compounds, also referred to as 5(6)-alkylthio-2-benzimidazole carbamate compounds. Such compounds are usedful as the active ingredients to combat infections of certain parasites in animals. The process of this invention produces compounds which demonstrate excellent activity against gastro-intestinal parasites such as mouse pinworm and sheep nematodes, and against migratory states of Ascaris suum in mice. In particular, the compounds produced by the process of this invention have been found to posses useful anthelmintic properties, that is, broad spectrum activity against parasites of warm blooded animals, including both mature and immature parasitic forms. In particular, these compounds have been found to exhibit high activity against various helmintic infections of the intestinal tract of economically important animals, coupled with low systemic toxicity to the host animals.
For example, compounds produced by the process disclosed are generally effective in clearing mice of worm infections for laboratory purposes, among others: Syphacia obvelata and Appliculuris tetraptera (mouse pinworm), Nematospiroides dubius (mouse hookworm), and the migratory stages of Ascaris suum.
Other susceptible helminths include Toxocara canis, found in naturally infested dogs. Also, parasitic to this host are Ancylostoma canium, Trichuris vulpis (whip-worm), and Physalaptera spp.
Compounds of this invention have been demonstrated as efficacious against parasites of pigs, such as the migratory stages of Ascaris suum, thus preventing the development of verminous pneumonia.
Compounds of this invention have also been demonstrated as efficacious against parasitic gastroenteritis in sheep, such as Haemonchus contortus, Ostertagia spp., Trichostrongylus spp., Nematodirus spp., Trichuris ovis, Cooperia spp., and Strongyloides papillosus. Bunostomum trigonocephalum and Oesophagostomum spp., are other important parasites of sheep.
In addition, compounds of this invention have also been found to have anthelmintic activity against parasites causing lungworm infections of animals. These parasites are of the Dictyocaulidae, Metastrongylidae, Protostrongylidae, and Filaroididae families, especially the genus Dictyocaulus which are prevalent in sheep, cattle and horses. They are particularly resistant to standard anthelmintic agents. Metastrongylus is important in pigs, Protostrongylus in sheep and goats, and Filaroides in cats and dogs. Certain lung-worms have been reported to be vectors for the influenza virus in swine.
Compounds of this type have been found to be especially useful and data supporting this use can be found in U.S. Pat. Nos. 3,915,986, 3,905,991, 3,574,845, 3,984,561, 3,997,553, 4,005,202, 4,010,272, 4,002,640, and 3,993,769, all of which are incorporated herein by reference as if fully set forth. Accordingly, the use, dosages and various formulations for compounds in accord with invention are fully disclosed in the prior art.